Measuring flow velocity of fluids is helpful in a variety of application, including for example research, metering, monitoring, and similar applications. One approach for monitoring flow is a so-called hot-wire anemometer. A hot-wire anemometer uses a heated wire positioned within the flow of media, such as gas, liquid, particle-laden liquid, or the like. As the media flows past the hot wire, heat is transferred from the hot wire to the media, cooling the hot wire. Flow can be determined from the temperature variation effects on the hot wire.
Hot-wire anemometers have proven useful for macroscale measurements. For example, hot-wire anemometers are used to monitor air flow within automobile engines, ventilation and heating ducts, and the like.
Less success has been achieved in using hot-wire anemometers in a microscale environment, such as microfluidics. Conventional macroscale hot-wire anemometers cannot easily be scaled into microscale dimensions. For example, as the scale of components is reduced, the components can become fragile and be easily damaged during the fabrication process. While micromachining techniques can be used to form small-scale structures, micromachining techniques are typically complex and time consuming.